extern statement

README.md

@@ -26,7 +26,7 @@ func main[] : I64
             io.print("Too high!")
 ```
 
-## Quick Start
+## Quickstart
 ```
 cargo install --git https://github.com/antpiasecki/zern
 zern -m -r hello.zr

examples/raylib.zr

@@ -1,42 +1,40 @@
-// musl doesnt like dlopen, needs to be compiled with -m
+// musl doesnt like dlopen, needs to be compiled with -m -C="/usr/local/lib/libraylib.a -lm"
 
 func main[] : I64
-    let rl: Ptr = c.dlopen("libraylib.so", 2)
+    extern InitWindow
+    extern SetTargetFPS
+    extern WindowShouldClose
+    extern BeginDrawing
+    extern EndDrawing
+    extern ClearBackground
+    extern CloseWindow
+    extern DrawRectangle
+    extern IsKeyDown
 
-    let rl.InitWindow: Ptr = c.dlsym(rl, "InitWindow")
+    let KEY_W: I64 = 87
-    let rl.SetTargetFPS: Ptr = c.dlsym(rl, "SetTargetFPS")
+    let KEY_S: I64 = 83
-    let rl.WindowShouldClose: Ptr = c.dlsym(rl, "WindowShouldClose")
+    let KEY_A: I64 = 65
-    let rl.BeginDrawing: Ptr = c.dlsym(rl, "BeginDrawing")
+    let KEY_D: I64 = 68
-    let rl.EndDrawing: Ptr = c.dlsym(rl, "EndDrawing")
-    let rl.ClearBackground: Ptr = c.dlsym(rl, "ClearBackground")
-    let rl.CloseWindow: Ptr = c.dlsym(rl, "CloseWindow")
-    let rl.DrawRectangle: Ptr = c.dlsym(rl, "DrawRectangle")
-    let rl.IsKeyDown: Ptr = c.dlsym(rl, "IsKeyDown")
-
-    let rl.KEY_W: I64 = 87
-    let rl.KEY_S: I64 = 83
-    let rl.KEY_A: I64 = 65
-    let rl.KEY_D: I64 = 68
 
     let x: I64 = 200
     let y: I64 = 200
 
-    rl.InitWindow(800, 600, "Hello, World!")
+    InitWindow(800, 600, "Hello, World!")
-    rl.SetTargetFPS(60)
+    SetTargetFPS(60)
 
-    while !rl.WindowShouldClose()
+    while !WindowShouldClose()
-        if rl.IsKeyDown(rl.KEY_W) & 255
+        if IsKeyDown(KEY_W) & 255
             y = y - 10
-        if rl.IsKeyDown(rl.KEY_S) & 255
+        if IsKeyDown(KEY_S) & 255
             y = y + 10
-        if rl.IsKeyDown(rl.KEY_A) & 255
+        if IsKeyDown(KEY_A) & 255
             x = x - 10
-        if rl.IsKeyDown(rl.KEY_D) & 255
+        if IsKeyDown(KEY_D) & 255
             x = x + 10
 
-        rl.BeginDrawing()
+        BeginDrawing()
-        rl.ClearBackground(0xffffffff)
+        ClearBackground(0xffffffff)
-        rl.DrawRectangle(x, y, 100, 100, 0xff0000ff)
+        DrawRectangle(x, y, 100, 100, 0xff0000ff)
-        rl.EndDrawing()
+        EndDrawing()
 
-    rl.CloseWindow()
+    CloseWindow()

src/analyzer.rs

@@ -87,6 +87,7 @@ impl Analyzer {
             }
             Stmt::Break => {}
             Stmt::Continue => {}
+            Stmt::Extern(_) => {}
         }
         Ok(())
     }

src/codegen_x86_64.rs

@@ -281,6 +281,9 @@ _builtin_set64:
                 // TODO: skips incrementing when used in a for loop
                 emit!(&mut self.output, "    jmp {}", env.loop_begin_label);
             }
+            Stmt::Extern(name) => {
+                emit!(&mut self.output, "    extern {}", name.lexeme);
+            }
         }
         Ok(())
     }

src/parser.rs

@@ -39,6 +39,7 @@ pub enum Stmt {
     Return(Expr),
     Break,
     Continue,
+    Extern(Token),
 }
 
 #[derive(Debug, Clone)]
@@ -198,6 +199,10 @@ impl Parser {
             Ok(Stmt::Break)
         } else if self.match_token(&[TokenType::KeywordContinue]) {
             Ok(Stmt::Continue)
+        } else if self.match_token(&[TokenType::KeywordExtern]) {
+            Ok(Stmt::Extern(
+                self.consume(TokenType::Identifier, "expected extern name")?,
+            ))
         } else {
             Ok(Stmt::Expression(self.expression()?))
         }

src/tokenizer.rs

@@ -47,6 +47,7 @@ pub enum TokenType {
     KeywordReturn,
     KeywordBreak,
     KeywordContinue,
+    KeywordExtern,
 
     Indent,
     Dedent,
@@ -334,6 +335,7 @@ impl Tokenizer {
             "return" => TokenType::KeywordReturn,
             "break" => TokenType::KeywordBreak,
             "continue" => TokenType::KeywordContinue,
+            "extern" => TokenType::KeywordExtern,
             "true" => TokenType::True,
             "false" => TokenType::False,
             _ => TokenType::Identifier,